A Study on Changes of Pigment Content in Leaves of 4 Color-leafed Species During Color Changing Period in Spring

Taking 4 color-leafed plants of Acer negundo, Amygdalus triloba, Ulmus pumila and Prunus cerasifera as experimental materials. The variation of photosynthetic pigment contenst, anthocyanin, leaf color parameters and pH value of leaves cytosol during the color changing period in spring were measured and analyzed in this study. The results showed that in terms of leaf photosynthetic pigment content, the total pigment content level of tree species with red leaf was higher than that of 2 tree species with golden leaf, and the total contents of chlorophyll and carotenoid showed regular High-low-high variation over time, but the variation of tree species with golden leaf is in a small range. The anthocyanin content of tree species with golden leaf showed a gentle downward trend, while the anthocyanin content of tree species with red leaf showed a 'M' trend which experienced high-low-high-low variation. The L^*values of the 3 color-leaf plants reached the highest level in early May, except A. triloba. The a^*values of the 2 trees species with red leaf also reached the peak in May, and then decreased gradually. The a^*value of the 2 golden leaf species increased slowly with time. The variation of b^*value of 4 tree species was opposite to that of a^*. The highest pH value of all the trees species appeared growth in the early stage and then showed a downward trend. In the early stage of spring, the chlorophyll content of the trees with golden leaf was low, while the content of carotenoids and anthocyanins was high. Under their joint action, the leaves of trees with golden leaf showed golden yellow in the early stage. In the early growth stage of trees with red leaf, the synthesis of chlorophyll and carotenoid was low, and anthocyanin was dominant, while the pH value of cell fluid promotes the color of anthocyanin, which made the leaves appear prunosus.